I think I have worked this out correctly....

The tank is roughly 40 Litres to fill.
I spend 80.9p a Litre most the time.
Thats 40 x 0.809 = £32.36 to fill up roughly.

4.45 UK Litres = 1 UK Gallon? (I think)

Thats 40/4.45 = roughly 8.99 Gallons.

I am getting about 250 Miles from my full tank all town driving which works out to be about....

250/8.99 = 27.81 MPG

Please feel free to correct me if I am wrong anywhere!!

Thanks

Chris